GCN Circular 8048
Subject
GRB 080727A: Early IR observations
Event
Date
2008-07-29T15:12:05Z (18 years ago)
From
Andrew Levan at U.of Leicester <anl@star.le.ac.uk>
A.J. Levan (U. Warwick) and K. Wiersema (U. Leicester) report for a
larger collaboration:
We observed the location of GRB 080727A (Immler et al. GCN
8021) using UKIRT. A series of K-band exposures were taken beginning at
06:24:51 UT, roughly 30 minutes after the burst, a total of 720s
of observtions were taken (36x20s). We find no evidence for any
source within the XRT error circle (Evans et al. GCN 8025) for GRB
080727A, down to a limit of K=19.8 mag (3-sigma).
Comparing this limit to the extrapolated X-ray flux 30 minutes
post-burst implies that the observed X-ray to optical/IR spectral
slope was beta_KX < ~0.8, thus the non-detection in the IR is likely
down to the rapid fading of the afterglow, rather than suppression
of the optical/IR flux.
We thank the staff of UKIRT for their rapid response to these alerts.